In general, a washing machine is an apparatus that performs a washing operation and improves washing effectiveness by forcibly forming a flow of washing water in a washing tub using mechanical force, by promoting chemical action of a detergent, and by applying a physical action such as friction or force to laundry.
The washing machine rotates a pulsator, which is installed at the bottom of the washing tub, in forward and reverse directions, thereby forming a water flow for the washing operation. Therefore, the washing machine needs to have a spin-drying shaft for rotating the washing tub, and a washing shaft for driving the pulsator. That is, the washing machine has a clutch for selectively driving the two drive shafts (the washing shaft and the spin-drying shaft). Accordingly, the clutch transmits rotational force generated by a drive motor to the pulsator during washing operations, and selectively transmits rotational force to the pulsator and the washing tub during spin-drying operations.
FIG. 1 is a cross-sectional view illustrating a general washing machine, and FIG. 2 is a perspective view illustrating a tub of FIG. 1. Referring to FIG. 1, a washing machine 10 has a main body (cabinet) 8 that defines its external appearance, and a tub 1 that is in the main body 8.
A washing tub 2, which is rotated by a drive motor 7, is provided in the tub 1, a pulsator 3 for a washing operation is provided at a bottom of the washing tub 2, and the pulsator 3 is rotated by the drive motor 7.
The drive motor 7, which produces rotational force for rotating the washing tub 2 and the pulsator 3, is provided at a lower side of the tub 1. The washing tub 2 receives rotational force from the drive motor 7 through a spin-drying shaft 5, and the pulsator 3 receives rotational force from the drive motor 7 through a washing shaft 6.
The spin-drying shaft 5 and the washing shaft 6 are installed concentrically, and the washing shaft 6 is positioned in the spin-drying shaft 5. The spin-drying shaft 5 and the washing shaft 6 are rotatably supported by a bearing housing 4.
Referring to FIG. 2, the tub 1 has a cylindrical shape, an upper portion of which is open. A hose member 11, which communicates with an overflow path (not illustrated) formed in an inner wall of the tub 1, is provided at one side of an outer surface of the tub 1.
However, the tub of the general washing machine in the related art is manufactured by general injection molding. This is problematic because it takes a long time to manufacture a mold because of the complicated structure of the tub, and consequently the cost of manufacturing the mold and the unit price of the tub are increased.
Also, a process for assembling the hose member and the like, which are provided separately from the tub, to the overflow path after injection molding of the tub is required. This is also problematic because the period of time required to manufacture the tub is further increased, and finishing and trimming work needs to be additionally performed on the coupling portions between the tub, the hose member, and the like.
Korean Patent Application Laid-Open No. 10-2010-0083208 (published on Jul. 22, 2010) describes an example of the related art.